Question for my mom

She had an abnormal mammogram in January. They repeated it some weeks ago and got an ultrasound. She had a biopsy done yesterday (not the fine needle one, but the one where they take a chunk of tissue from 3 different places). She has to wait 10 days for the results.
All she knows is that she'll need to have the nodule removed either way.
The surgeon says he doesn't care about the biopsy results, with the mammogram and ultrasound he can perform the surgery and if needed he can get the sentinel lymph node at a later time.
Now, should she wait for the results?. Or start on the surgery?. Can surgery make it worse?. Can the surgeon diagnose cancer after the surgery based on what he saw, took out, etc?.
The reason I'm asking here is that I'm in Nebraska and she's in Argentina so it's impossible at the moment to ask her doctor directly. To make it worse she insisted on going alone to her appointments so far..
Thanks a lot!
Dolores